President Moon Jae-in speaks with Japanese Prime Minister on the phone on March 16 to discuss the latest developments with North Korea. / Yonhap

By Yi Whan-wooJapan is stepping up efforts to join talks with North Korea after stressing the importance of sanctions over dialogue for Pyongyang's denuclearization.Some diplomatic sources say Tokyo's abrupt shift in its North Korea policy is to avoid being left behind, as the other five stakeholders of the Korean Peninsula including the U.S., China and Russia, have thrown their support behind inter-Korean reconciliation.Other sources say Japanese Prime Minister Shinzo Abe is trying to divert public attention amid a mounting scandal involving his wife and the sale of state-owned land.Japan had remained skeptical about dialogue with North Korea despite a series of reconciliatory steps between the two Koreas since January, such as the announcement on March 6 of a planned summit between President Moon Jae-in and North Korean leader Kim Jong-un.Japan was then surprised when U.S. President Trump on March 9 accepted North Korean leader Kim Jong-un's offer to meet and said they would hold a summit by the end of May.Trump's decision triggered Japanese Prime Minister Shinzo Abe's decision to hold an unexpected summit between the two leaders in April.The sources said Abe's treatment of National Intelligence Service director Suh Hoon was a possible sign he was beginning to take dialogue with North Korea seriously and was seeking the South's cooperation.Abe was previously criticized in Seoul for not being courteous to the presidential envoy and other South Korean officials when he had them sit in lower chairs than his own.Suh was one of Moon's envoys to North Korea from March 5 to 6 and briefed Abe in Tokyo on March 13 about his Pyongyang trip after visiting the White House.During his phone call with Moon on March 16, Abe agreed to work together to resolve pending issues between North Korea and Japan, especially regarding the issue of Japanese nationals kidnapped by North Korean agents in the 1970s and 1980s.The two leaders also agreed on working-level discussions to arrange Moon's possible visit to Japan as well as their meeting with Chinese President Xi Jinping at the earliest possible date.

Japanese Prime Minister Shinzo Abe, right, talks with National Intelligence Service director Suh Hoon, one of President Moon Jae-in's envoys to North Korea, during Suh's visit to Tokyo on March 13. / Yonhap

Meanwhile, South Korea and the U.S. have been pushing to cooperate for their historic summits in April and May.Moon had a separate phone call with Trump on March 16, during which they stressed the importance of denuclearizing the Korean Peninsula, according to Moon's chief press secretary Yoon Young-chan."The President said it is the most important goal and process in order to secure peace in the world, let alone the Peninsula," Yoon said.Moon and Trump expressed "cautious optimism" over recent developments and emphasized that "a brighter future is available for North Korea if it chooses the correct path."The White House noted the two leaders' resolve to make sure the North upholds its stated commitment to denuclearization."Both leaders affirmed the importance of learning from the mistakes of the past, and pledged continued, close coordination to maintain maximum pressure on the North Korean regime," it said, referring to economic and diplomatic sanctions on the North."The two leaders agreed concrete actions, not words, will be the key to achieving permanent denuclearization of the peninsula, and President Trump reiterated his intention to meet with North Korean Kim Jong-un by the end of May."

On the ministerial level, Japanese Foreign Minister Taro Kono met his South Korean counterpart Kang Kyung-wha on March 17 in Washington, D.C., and promised to strengthen coordination on North Korea-related issues.According to the South Korean government, Kono and Kang exchanged views mainly on North Korea and Seoul-Tokyo ties, with both sides agreeing that the planned summits between Seoul and Pyongyang, and between Washington and Pyongyang, would become an important turning point in the impasse over North Korea's nuclear weapons program.Kang noted Japan had been sending "positive messages" on its willingness to improve ties with North Korea and bring peace to the peninsula and beyond. She called on Japan to help maintain the momentum for dialogue with North Korea, which began with the North's participation in the PyeongChang Winter Olympics.Kono "assessed the South Korean government's active efforts for denuclearization of the Peninsula" and expressed hope that improvement in South-North ties would eventually help resolve Tokyo-Pyongyang issues.They agreed to work closely to arrange a trilateral summit with China at an early date, while discussing Moon's possible visit to Japan as well as Kono's possible trip to Seoul.Kang separately met U.S. Deputy Secretary of State John Sullivan March 16, also in Washington, D.C., to discuss recent developments between the two Koreas and between the North and the U.S.Sullivan is temporarily replacing former U.S. Secretary of State Rex Tillerson after Trump sacked him abruptly."We agreed the inter-Korean summit in April and the U.S.-North Korea summit to be held by May will be important turning points," Kang said after the meeting."We agreed to work together to ensure they become a historic milestone for denuclearization and lasting peace on the peninsula."The U.S. State Department said in a statement that Kang and Sullivan reaffirmed the South Korea-U.S. alliance was "the lynchpin of stability and security in the region," particularly in light of North Korea's nuclear and ballistic missile programs."Both sides agreed the announcement of a meeting between President Trump and North Korean leader Kim Jong-un is a historic opportunity and evidence that the global maximum pressure campaign is working and must remain in effect," the statement said. Kang and Sullivan also agreed "international pressure on North Korea must be maintained until the regime takes credible, verifiable and concrete steps toward denuclearization," according to the department.On March 19, the two Koreas and the U.S. held a three-way meeting among their former government officials and scholars in Finland to discuss the latest developments on North Korea.Seoul said the "1.5-track" meeting involved 18 people, six from each of the three nations.North Korea's Deputy Director-General for North American Affairs Choe Kang-il represented Pyongyang.The U.S. delegation included former U.S. ambassadors to South Korea Kathleen Stephens and Thomas Hubbard as well as academics Bob Carlin, John Delury and Karl Eikenberry.The South Korean side included former ambassador to Japan Shin Kak-soo, former ambassador to China Shin Jung-seung and Handong Global University professor Kim Joon-hyung.Pyongyang and Washington initially planned the meeting, but then decided to include Seoul according to sources."This meeting could serve as a chance to prepare for the inter-Korean summit and the U.S.-North Korea summit," a source said.